Dental impression tray



Nw. 13, 192s. 1,691,676

E. R. SMITH DENTAL IMPRES SION TRAY Filed May 18, 1926 /N VEN rahTrama-rsA Patented Nov. 13, 17928.

V.narran srA'res eArEj ERNEST ROBERT SMITH, 0E SAN FRANCISCO,oALiroRiviA.

nEivTArJ TIaPREssroN TRAY.

Application filed May 18,

AThis invention relates generally to trays empioyed by dentists fortaking impressions of the teeth.

Dental trays employing separable elements are now in common use, oneform being shown in my vPatent No. 1,422,488, issued July 11, 1922, ofwhich the invention herein disclosed is an improvement. In the structureshown in the above patent, the tray is formed of two separable sectionswhich are retained together by a single nut, the nut having threadedengagement with a pair of complementary posts or studs secured to therespective tray sections.- lVhile such construction is an improvementover other forms of trays, it requires considerable time to engage thenuts with the threaded posts, and the sections cannot be quicklyseparated when positioned within the oral cavity of a patient.

It is an object of this invention to devise a fastening meansfordetachably securing the sections of a separable dental tray wherebythe sections may be quickly secured together and separated. Y

- It is a furtherobject of this invention to construct a securing meansfor a separable dental tray in the form of a nut having cam faces whichengage pins or projections secured to the sections of the tray.

Further objects of the invention will appear from the followingdescription in which I have set forth the preferred embodiment of myinvention. It is to be understood that the scope of this invention is tobe determined from the appended claims taken in connection with theprior art.

Referring to the drawings:

Figure 1 is a bottom plan view of a dental tray employing the'principles of this invention. l

Fig. 2 is a detail showing the construction of the cam faces for theclamping nut.v Fig. 3 is a view similar to Fig. 1 with the clamping nutremoved. Y

F ig. 4 is a cross section taken along the line 4-4 of Fig. 1.

The device comprises generally a dental tray 10 of any desired shapewhich is split along the dividing line 11 to form a pair ofcomplementary tray sections 12 and 13. In

the particular form of dental tray illustrated the tivo sections areL-shaped in cross section, the two portions 14 and 15 forming the basefor the tray. The two portions 14 and 15 of the sections are preferablyprovided with ieee. serial no` 103,856.

flanges 16 and 17 whose opposed surfaces 'are adapted to be brought intoclamping engage ment. Y I k For clamping the two' sections/togetheralong the dividing line 11 the base of the tray is preferably providedwith apluralityof projcctionsor pins 19 which are preferably providedwith'heads 20. In the particular Y construction shown three. projections19 have been employed, one projection Aloein,f `upon one of the traysections while the other two projections are upon'the other section. Inorder to detachably engage the proj ections`19 for clamping the sections12 and 13 together, there is provided a nut'22 which is preferably Lpertured as at 23 to provide a plurality ofV inner cam faces 24.' Eachof the cam faces 24 cut along an arc having a radius of greater lengththan the distance between that particular cam face and the centralintermediate point 25 between the camfaces. BetweenV the cam faces arethe cut-away portions 26, the number of cut-away portions and lof thecam faces 24 being equal to the number of projections 19.

lhen the tray sections 12 and 13 are positionecl in complementaryrelationship the nut 22 is adapted to be positioned over the projections19 and: upon rotation of the .nut in either direction each of the camfaces 24V engage a projection 19 to effectively force the projectionstogether and therefore clamp together the tray sections along theVdividing line. The heads20v upon the projections prevent accidentalremoval of the-nut after being rotated in clamping position. v The innerface 28 of the nut is preferably a plane surface which is adapt-ed tofit iiush against the bottom surface of the tray whereby it will serveto reinforce the tray sections whenI in clamping position. Y

vVhen securing the two sections togetherit is desirable to have somemeans for matching `together the opposed surfaces ofthe flanges 16 and17 to insure accurate positioning of the dental tray sections vand tofacilitate positioning of the nut 22 upon the projections 19.

This is accomplished by providing a small pin 29 secured to one of thetray sections and partly projecting so as to interrupt the dividing line11. The complementary surface of the other section is recessed so astofit around the projecting portion of this pin whereby in positioning`the two sections together the flanges 16 and 17 must be matched Vbefore`dividing iiiiiJ 11.

their opposed surfaces will meet along the In using the device the twotray sections 12 Vand 13 are matched together andV detachably clamped byrotation of the'nut 22 in either direction. Suitable plastic material isthen placed lWithin the trayA and it is inserted over the teeth of apatient for taking the desired impression. When the plastic material hasset the lnut 22 may be readily removed While theftray is 'Within theoral cavity ci the patient, and the two sections then separated toremove the impression.

"1. A dental impression tray comprising a pair-of'complementary sectionsmeans including a nut having a plurality or symmetrically vdisposed cam'faces `for detachably clamping and unclamping said sections by arotation of said nut in eitherV direction..

Y `2. A device ofthe class described comprising a tray having arelatively fiat base, said tray being split along a line intermediatesaid base Vthereby forming a pair of separable sections, at least oneprojection fixed to cach section on said base, said projections havingheads, and an apertured nut having inner cam faces adapted to engagesaid projections under said heads whereby said sections may be clampedtogether upon rotation of the nut.

3. A device of the class described comprising a tray having a relativelyflat base, said i- A sectional dental impression tray provided withmeans comprising a ilat cam apertured disk for detachably securing thesections of said tray. j

5. A'dental impression tray comprising a pair of complementary7sections, lmeans including a nut having a plurality of cam `faces fordetachably clamping said sections together on rotation of the nut ineither direction.

6. A dental impression tray comprising a pair of complementary sectionsand means including an apertured plate for detachably clamping saidsections, the vnlls or the aperture in said plate delining a pluralityof symmetrically disposed cam surfaces.

7. A sectional dental impression tray and detachable means provided Witha central symmetrically scalloped aperture tor detachably securing thesections of said tray.

In testimony whereof, I have hereunto set my hand. f f

ERNEST ROBERT SMITH.

